Electric switch



Dec. 17, 1929. Y A g. GAYNOR 1,739,835

ELECTRIC swn'cn Original F iledjug. 2. 1926 2 Sheets-Sheet 1 22 69 5.8 I "6 wgnwzn 1o I N VEN TOR.

76 ATTORNEYS Dec. 17, 1929.

'l A. c. GAYNOR 1,739,835

. ELECTRIC swnca Original Filed Aug. 2. 1926 2 sheets-sheer z 56 x22. 112223; 16 20 \v V 4.9 Q

- INVENTOR. M 175 NEYJ Patented Dec. 17, 1929 UNITED STATES PATENT OFFICE ARTHUR C. GAYKOR, OF STRATEORD, CONNECTICUT Original application nnnc'rnrc swrrcn filed August 2, 1926, Serial No. 126,530, new Patent No. 1,690,780, dated November 6, 1928. Divided and this application filed January 10, 1927. Serial No. 160,211.

This invention relatesgenerally to electric switches but has to do, more particularly, with electric switches of the snap type.

One object of the present invention is to provide an electric snap switch of such construction that arcing, when the circuit is broken, will be substantially entirely elimi-v nated.

Another object of the invention is the provision of a snap switch construction which will permit the switch to be easily and expeditiously produced and assembled at an exceedingly low cost both for the material contained therein as well as assembify for the several parts.

Other objects contemplated by the present invention relating to details and economy in construction and operation will definitely appear from the detailed description which follows. In one instance, the several objects of the invention are accomplished by devices and means set forth in detail in the following specification, the particular features sought to be covered in the present case being clearlypoi-nted'out in the appended claims.

'One form of switch constituting the preferred'embodiment of the invention is illustrated in the accompanying drawings, wherein Figure 1 is a plan view of the switch embodying the present improvements.

Fig. 2 is a vertical sectional view of the switch on the line 22 of Fig. 1.

V Fig. 3 is a plan view of the switch with the bridge plate and insulating strip removed therefrom.

Fig. 4 is an end elevation of the operating assembly of the switch removed from the in sulating base.

Fig. 5 is a sectional view taken on the line 5'5 of Fig. 4. v

Fig. 6 is a sectionalview taken on theline 6--6 of Fig. 1. i

Fig. -7 is a sectional viewon the line 7-7 of Fig. 2.

Fig. 8 is an enlarged perspective view of the bra ket which forms a support in the base for the operating parts.

Fig. 9 is an enlarged perspective view of the crank shaft.

As stated above, one object of the invention is to provide a snap switch construction in which arcing will be more effectively overcome than in prior switches of the present type. Opening an electric circuit is attended, in many cases, by a rise in the voltage in'the circuit adjacent to the point of opening. This is often sufficient to overcome the resistance of the air and raise the temperature to such a degree that the current will persist, thereby creating an arc. It is proposed in the present improved snap switch to prevent the formation of such an are by providing insulating material of much greater heat capacity than air and of good heat absorbing qualities located very close to the path which the contact blade takes as it is disengaged from the contact jaw. It is proposed to put the insulating materialof the base, or that portion of it adjacent the contact blade and the contact jaw, in such a way as to increase its capacity for absorbing heat so that the heat generated by the'opening of the circuit which would otherwise tend to create an arc is readilyabsorbed by that portion of the base adj acent to such joints of contact.

Snap switches usually include at least'two contact jaws, one of which is customarily located near the bottom of the insulating base and is provided with a vertical lead running upward to the top face of the base so that an arc is apt to become established between this vertical lead and the contact blade. In view of this the formation of an are by rea-' son of this'construction is sought to be prevented by the interpositioning of a solid in-. sulating barrier between such vertical lead from the contact jaw and the path of movement of the adjacent end of the contact blade which engages said jaw. To this end there is provided a laterally offset recess at the end of the slot in the insulating base, in which the contact blade moves, and the vertical lead in the contact jaw is offset so that it is located in an offset recess of the base.

A further object contem lated by the present case which tends to reduce the cost of manufacture of the present switch is the elimination of the screws customarily used for maintaining the contact jaws in position on the base. To this end the formation of the base and of the contact jaws is such that the latter is held against all movement with respect to the base, except a vertical movement, and to prevent such vertical movement there is a bridge plate which extends over said contact members and clamps them against the base.

In the accompanying drawings illustrating a preferred embodiment of the present in vention the insulating base 10 is provided with a recess or socket 11 which receives the operating parts of the switch and with a slot 12 communicating with said recess and receiving) the contact jaws and the movable contact lade. It is preferred to make the base of porcelain and to treat certain portions thereof, that is, the walls of the slot 12 which receive the contact blade and the contact jaws by spraying a coating of lacquer thereon in order to increase the heat absorbing qualities of those portions of the base for the purpose of preventing arcing. It has been found,

however, that a satisfactory result is obtained by forming the base of bakelite or of cold molded insulation, a material well knowii on the market and consisting of a pressed and baked mixture of pitch and asestos. If the base is made of bakelite or cold molded insulation, no further treatment is necessary in that it possesses the necessary heat absorbing qualities for the prevention of arcing. On the. other hand, if porcelain be used that portion of the base adjacent the path of the'contact blade should be sprayed with lacquer as just described. It has also been ascertained that the applicationof. a coating of paint or paste tosu'ch portions of the base will so increase their heat absorbing qualities as to ive the result wished for in preventing the ormation of an arc.

The insulating base has terminal seats 13 formed therein and transverse grooves 15 are provided in the upper surface of the base leading from opposite ends of the slot 12 to said terminal seats. A hole 14 is formed in each terminal to receive thelower end of a binding screw 20. The contact jaws 17 and 21 are located in the slot 12 at opposite ends thereof, the contact jaw 17 being located near the to of the slot while the jaw 21 is located near t e bottom thereof. *The contact 'aw 17 is formed integral with'a lead portion 18 which extends transversely of the base in one of the grooves 15 and is provided with a terminal portion 19 seating on the terminal seat 13. A binding screw 20 is screwed into the terminal portion 19 and pro ects into the corresponding hole 14. *The contact jaw 21 has formedintegral therewith a vertical portion 22 which is positioned in an offset vertical recess 16 formed in thebase at the cor responding end of slot 12, as shown in Fig. 7. On the upper end of this vertical portion 22 there extends a transverse portion 18 fitting in the corresponding slot 15 and ending in a terminal portion 19 in the seat 13, said terminal portion receiving a binding screw 20 which projects into the hole 14 as in the case of the contact member at the opposite end of the base. The contact jaw is offset as at 23 from the lower end of the vertical portion 22.

The operating parts of the switch are supported by a sheet metal bracket comprising the top plate 24 having thecentral opening 29 therein through which the actuator lever 39 extends, and a pair of spaced depending arms 25. .Each of these arms 25 has a bearing 26 formed therein for the crank shaft and is provided with an entrance slot 27 through which the crank shaft may be inserted. One arm 25 has lugs 28 thereon which act as stops to limit the oscillatory movement of the crank shaft in the bearing, said shaft is made of a piece. of wire bent to required form, being provided with ou'tturned bearing portions 31 which are journal'ed'in the bearings 26 of the shaft arms 25. The crank portion 32 of said shaft is located between said arms, the central portion of the crank being bent upwardly to form the hump 33 which provides a seat for the compression spring 36. The wire forming the crank shaft has a lateral projection 34 extending from the end of this bearing portion 31 and a part 35 bent back parallel to said portion 31, thereby forming a non-circular projecting end on said crank shaft by means of which a non-rigid connection is made between said shaft and the contact blade 60. The coil spring 36 is compressed between the hum shaft and the lower end of actuator lever 39, the lower end of'said lever having an edge portion 37 of semi-circular outline with a pair of shoulders 38 adjacent said semicircular portion. This forms the spring seat V for the upper end of coil spring 36 the semicircular portion 37, of said lever fitting within the end of the coil spring and preventing its displacement while the hump 33 on the crank fits within the opposite or lower end of said spring 36. Certain details involved in this actuating mechanismlconstitute subjectmatter of applicants prior application Serial No. 126,530, filed August 2, 1926, of which the present case is a division,,and for this reason it is not believed a more detailed description of these parts is necessary in the present case.

A seat is formed in the the insulating base 10 of such a size and shape that the top plate 24 of the bracket fits therein said bracket being held against movement in'a horizontal plane by cooperation of said top plate with'such seat. Astrip 56 of suitable insulating material is applied to the up: per surface of the base and extends across top plate 24 of the bracket as well as across the contact leads 18 in the grooves 15 of the base.

A bridge plate 57 is positioned on top of this 33 on the crank upper surface of strip of insulating material and has the usual ofiset ends 58 provided with openings by means of-which the switch, completely assembled,-may be secured in position. This bridge plate is secured to the insulating base by means of screws 59 extending from the bottom of the base through holes formed therein and screwed into said bridge plate, said bridge plate, therefore, serves to clamp the leadsl8 in the grooves 15 and to clamp the bracket 24 in its position in the seat 50, thereby preventing any vertical movement of all of suchparts.

The operation of this switch construction should be a parent from the foregoing description n Fig. 2 the parts of the switch are shown in position to close the circuit between th contact jaws 17 and 21. When the operatorwishes to break the circuit he moves the actuator lever 39 to the right as seen in Fig. 2, thereby causing the lower end of the actuator-lever to move from right to left and since the spring seat 37 formed at the lower end of said lever acts upon the upper end of the spring and compresses it between said seat and the crank portion of the crank shaft, this movement-of the lower end of the actuator lever frdm right to left will first tend to compress more strongly the spring 36, and. then, as the lower end of said lever passes the center line, this compressed spring will act upon the crank portion of shaft 31 and impart a snap movement of oscillation thereof. This causes the crank shaft to rotate quickly and swing the contact blade 60 out of engagement with the contact jaws 17 and 21. After being thus disengaged a movement of the actuating lever from right to left will correspondingly impart a snap movement to the crank shaft and contact blade carrying the contact blade into engagement with the jaws and closing the circuit once more.

It will be noted that the walls of slot 12 are close toithevpath of movement of the contact A blade 60. When the circuit is broken there is a tendency for the creation of an are between the end of the contact blade and the adjacent contact jaw but the walls of the slot are located so close to the path of movement of the contact blade and are formed of material having such heat absorbing qualities that the heat is absorbed by said walls and the air does not increase in temperature to a point sufficient to create an arc. There is also a tendency toward the formation of an I are bet' ween the end of a contact blade and the vertical lead 22 of lower contact jaw 21, but any arcing that may take place at this point is quenched by having such vertical lead located in an offset recess 16-at the end of slot 12. With this construction the corner or shoulder formed at the edge of the recess 16 presentsa solid barrier of insulating niaterial between such lead 22 and the path of the contact blade (30 thereby preventing arcing at this point The cooperation of the transverse portions 18 of the contact members and the lateral grooves 15 in the base serves to prevent any movement of the contact jaws lengthwise of slot 12, movement of said jaws transversely of the slot is prevented by the projection of the binding screws 20 in holes 14 of the terminal seats. Vertical movement of the con tact jaws in slot 12 is prevented by clamping action in the bridge plate 57. This makes a very simple and cheap assembly in that it eliminates two fastening screws heretofore customarily em loyed for attaching the contact jaws to the ase.

The bracket 24 is seated in seat 50 at the upper surface ofthe insulating base and said seat confines said bracket against movement in a vertical direction. However, the bridge plate serves to clamp this bracket and the operating parts carried thereby against vertical movement so that this also lends to the simplification and cheapness of construction in which the assembly can be performed very quickly and expeditiously, simply by screwing the bridge plate in position which secure ly clamps the several parts in place.

Certain features of this invention are not necessarily limited to use in snap switches and in so far as it is applicable only to snap switches it is no. to be limited to snap switches which are actuated by a lever as many features are also applicable to switches of that type which are actuated, say, by a rocker member under the control of push buttons.

What I claim is:

1. In an electric switch, the combination of a porcelain base having a slot therein, the

walls ofsaid slot having a coating of lacquer 7 applied thereto, fixed contacts located at opposite ends of'the slot, and a contact blade movable in said slot into and out of engagement with said contacts.

2. In anelectric switch, the combination of a base of insulating material having a cavity therein to receive the operating parts, a pair of fixed contacts located in said cavity, one near the top and the other near the bottom thereof, the latter having a vertical portion extending to the top of the cavity, and a contact blade movable in said cavity into and out of engagement with said contacts, the vertical portion of said lower contact being located radially beyond the path of said blade and said base having a portion inter osed A as a barrier between the path of said lade and the vertical portion of the lower contact to prevent arc-ing therehetween.

3. In an electric switch, the combination of a base of insulating material having a cavity to receive the operating arts, a slot opening into said cavity, one on portion of said slot being ofiset laterally to rovide a vertical recess, fixed contacts locate inoppo- Y site ends of said slot, one near the bottom thereof, the latter having a vertical lead located in said offset recess and extending to the top of the slot, and a contact blade moving in said slot into and out of engagement with said contacts.

4. In an electric switch, the combination of a base of insulating material, a movable contact blade, said base having a recess in which said blade works, a contact member to be engaged by said blade, said base and con tact member being so formed as to prevent movement of the latter lengthwise or. crosswise of the recess, and a bridge fastened to the top of the base and preventing movement of the contact member vertically in the recess.

5. In an electric switch, the combination of a base of insulating material having a recess in which a movable contact blade works, and a transverse groove in its top face, a contact member located in said recess and having a portion seated in said groove, whereby movement of the member lengthwise of the recess is prevented, and a bridge fastened to the top of the base and preyenting movement of the contact member vertlcally in the recess. 6. In an electrical switch, the combination of a base of insulating material having a recess in which a movable contact blade works,

a contact member located in said recess and having a portion co-acting with a portion of the base to prevent movement of the member lengthwise of the recess, a binding screw screwed into a portion of said contact member, said base having a hole into which said screw projects to prevent movement of the contact transversely of the recess, and a bridge fastened to the to of the base and preventing movement of t e contact vertically in the recess.

7. In an electric switch, the combination of a base of insulating material havinga slot in I which a movable contact blade works, a transverse groove in the to face extending from one end of the slot, 'an a terminal seat with a hole formed therein, a contact member having a contact jaw located in one end of said slot, a portion seated in said transverse groove and a terminal seated on said terminal seat, a binding screw screwed into said terminal and projecting into the hole in said seat, a strip of insulating material applied to the top of said base and extending over the portion of the contact member in said groove, and a bridge fastened to the base and extending over said strip of insulating material.

ARTHUR c. eAYNoRf 

